DYNAMICS OF TURBULENT AIR-FLOW IN DROPLET DRIVEN SPRAYS

This paper presents a study of the fundamental mechanics of droplet an d gas motion in sprays. Only vertical sprays are considered and our th eoretical analysis identifies two main flow zones, corresponding to wh ere the droplet velocity is much greater than or of the same order as the induced air velocity . Analytical asymptotic results for the induc ed air velocity for small and large downstream distances confirmed a f ull numerical calculation and also agreed with experimental results. T he second half of the paper deals with some of the most important aspe cts of spray jets in a cross flow. We find that the ratio of the cross -wind speed to the induced air jet speed U0/V(j) is a crucial factor f or specifying the dynamical behaviour. We present results for an axi-s ymmetric spray in uniform cross flow for both weak and strong cross-wi nds.